Hand held blood analyte measurement systems are used for testing an individual's blood in a variety of surroundings at any time of day. These systems typically comprise an analyte meter that is configured to receive a biosensor, usually in the form of a test strip. Because these systems are portable, and testing can be completed in a short amount of time, patients are able to use such devices almost anywhere in the normal course of their daily lives without significant interruption to their personal routines. Therefore, a person with diabetes may measure their blood glucose levels several times a day as a part of a self management process to ensure proper control of their blood glucose within a target range. In the course of conducting typical day to day activities, the individual may perform a blood glucose test in a variety of locations under various ambient lighting conditions, such as in an airport, while seated in a darkened movie theater, outside in a park, or dining at a restaurant.
There currently exist a number of available portable electronic devices that can measure analyte levels in an individual based on a small sample of blood. Different test strips perform different analyte measurements and must be automatically identified by the analyte meter when a sample is provided to the meter by a user inserting the test strip into a test strip port. Typically, an LED at the test strip port illuminates the test strip while a photodiode at the test strip port detects properties of the response by the test strip to the LED light in order to identify the type of test strip that has been inserted. Such detection systems operate effectively so long as ambient light does not interfere with the photodiode. In bright daylight, for example, the photodiode may be adversely affected and may drive its associated detection circuitry into saturation, thereby preventing an accurate reading of the test strip type.